text: /*
   * Copyright (c) 1997-1999 Massachusetts Institute of Technology
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  
  /*
   * rexec.c -- execute the fft
   */
  
  /* $Id: rexec.c,v 1.26 1999/10/26 21:41:35 stevenj Exp $ */
  #include <stdio.h>
  #include <stdlib.h>
  
  #include "fftw-int.h"
  #include "rfftw.h"
  
  void rfftw_strided_copy(int n, fftw_real *in, int ostride,
  			fftw_real *out)
  {
       int i;
       fftw_real r0, r1, r2, r3;
  
       i = 0;
       for (; i < (n & 3); ++i) {
  	  out[i * ostride] = in[i];
       }
       for (; i < n; i += 4) {
  	  r0 = in[i];
  	  r1 = in[i + 1];
  	  r2 = in[i + 2];
  	  r3 = in[i + 3];
  	  out[i * ostride] = r0;
  	  out[(i + 1) * ostride] = r1;
  	  out[(i + 2) * ostride] = r2;
  	  out[(i + 3) * ostride] = r3;
       }
  }
  
  static void rexecutor_many(int n, fftw_real *in,
  			   fftw_real *out,
  			   fftw_plan_node *p,
  			   int istride,
  			   int ostride,
  			   int howmany, int idist, int odist,
  			   fftw_recurse_kind recurse_kind)
  {
       int s;
  
       switch (p->type) {
  	 case FFTW_REAL2HC:
  	      {
  		   fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, out + s * odist,
  				out + n * ostride + s * odist,
  				istride, ostride, -ostride);
  		   break;
  	      }
  
  	 case FFTW_HC2REAL:
  	      {
  		   fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, in + n * istride + s * idist,
  				out + s * odist,
  				istride, -istride, ostride);
  		   break;
  	      }
  
  	 default:
  	      for (s = 0; s < howmany; ++s)
  		   rfftw_executor_simple(n, in + s * idist,
  					 out + s * odist,
  					 p, istride, ostride,
  					 recurse_kind);
       }
  }
  
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  
  /* rexecutor_many_vector is like rexecutor_many, but it pushes the
     howmany loop down to the leaves of the transform: */
  static void rexecutor_many_vector(int n, fftw_real *in,
  				  fftw_real *out,
  				  fftw_plan_node *p,
  				  int istride,
  				  int ostride,
  				  int howmany, int idist, int odist)
  {
       switch (p->type) {
  	 case FFTW_REAL2HC:
  	      {
  		   fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;
  		   int s;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, out + s * odist,
  				out + n * ostride + s * odist,
  				istride, ostride, -ostride);
  		   break;
  	      }
  
  	 case FFTW_HC2REAL:
  	      {
  		   fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;
  		   int s;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, in + n * istride + s * idist,
  				out + s * odist,
  				istride, -istride, ostride);
  		   break;
  	      }
  
  	 case FFTW_HC2HC:
  	      {
  		   int r = p->nodeu.hc2hc.size;
  		   int m = n / r;
  		   int i;
  		   fftw_hc2hc_codelet *codelet;
  		   fftw_complex *W;
  
  		   switch (p->nodeu.hc2hc.dir) {
  		       case FFTW_REAL_TO_COMPLEX:
  			    for (i = 0; i < r; ++i)
  				 rexecutor_many_vector(m, in + i * istride,
  						       out + i * (m*ostride),
  						       p->nodeu.hc2hc.recurse,
  						       istride * r, ostride,
  						       howmany, idist, odist);
  
  			    W = p->nodeu.hc2hc.tw->twarray;
  			    codelet = p->nodeu.hc2hc.codelet;
  			    HACK_ALIGN_STACK_EVEN;
  			    for (i = 0; i < howmany; ++i)
  				 codelet(out + i * odist, 
  					 W, m * ostride, m, ostride);
  			    break;
  		       case FFTW_COMPLEX_TO_REAL:
  			    W = p->nodeu.hc2hc.tw->twarray;
  			    codelet = p->nodeu.hc2hc.codelet;
  			    HACK_ALIGN_STACK_EVEN;
  			    for (i = 0; i < howmany; ++i)
  				 codelet(in + i * idist,
  					 W, m * istride, m, istride);
  
  			    for (i = 0; i < r; ++i)
  				 rexecutor_many_vector(m, in + i * (m*istride),
  						       out + i * ostride,
  						       p->nodeu.hc2hc.recurse,
  						       istride, ostride * r,
  						       howmany, idist, odist);
  			    break;
  		       default:
  			    goto bug;
  		   }
  
  		   break;
  	      }
  
  	 case FFTW_RGENERIC:
  	      {
  		   int r = p->nodeu.rgeneric.size;
  		   int m = n / r;
  		   int i;
  		   fftw_rgeneric_codelet *codelet = p->nodeu.rgeneric.codelet;
  		   fftw_complex *W = p->nodeu.rgeneric.tw->twarray;
  
  		   switch (p->nodeu.rgeneric.dir) {
  		       case FFTW_REAL_TO_COMPLEX:
  			    for (i = 0; i < r; ++i)
  				 rexecutor_many_vector(m, in + i * istride,
  						 out + i * (m * ostride),
  					       p->nodeu.rgeneric.recurse,
  						   istride * r, ostride,
  						       howmany, idist, odist);
  
  			    for (i = 0; i < howmany; ++i)
  				 codelet(out + i * odist, W, m, r, n, ostride);
  			    break;
  		       case FFTW_COMPLEX_TO_REAL:
  			    for (i = 0; i < howmany; ++i)
  				 codelet(in + i * idist, W, m, r, n, istride);
  
  			    for (i = 0; i < r; ++i)
  				 rexecutor_many_vector(m, in + i * m * istride,
  						       out + i * ostride,
  					       p->nodeu.rgeneric.recurse,
  						   istride, ostride * r,
  						       howmany, idist, odist);
  			    break;
  		       default:
  			    goto bug;
  		   }
  
  		   break;
  	      }
  
  	 default:
  	    bug:
  	      fftw_die("BUG in rexecutor: invalid plan\n");
  	      break;
       }
  }
  
  #endif /* FFTW_ENABLE_VECTOR_RECURSE */
  
  void rfftw_executor_simple(int n, fftw_real *in,
  			   fftw_real *out,
  			   fftw_plan_node *p,
  			   int istride,
  			   int ostride,
  			   fftw_recurse_kind recurse_kind)
  {
       switch (p->type) {
  	 case FFTW_REAL2HC:
  	      HACK_ALIGN_STACK_ODD;
  	      (p->nodeu.real2hc.codelet) (in, out, out + n * ostride,
  					  istride, ostride, -ostride);
  	      break;
  
  	 case FFTW_HC2REAL:
  	      HACK_ALIGN_STACK_ODD;
  	      (p->nodeu.hc2real.codelet) (in, in + n * istride, out,
  					  istride, -istride, ostride);
  	      break;
  
  	 case FFTW_HC2HC:
  	      {
  		   int r = p->nodeu.hc2hc.size;
  		   int m = n / r;
  		   /* 
  		    * please do resist the temptation of initializing
  		    * these variables here.  Doing so forces the
  		    * compiler to keep a live variable across the
  		    * recursive call.
  		    */
  		   fftw_hc2hc_codelet *codelet;
  		   fftw_complex *W;
  
  		   switch (p->nodeu.hc2hc.dir) {
  		       case FFTW_REAL_TO_COMPLEX:
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    if (recurse_kind == FFTW_NORMAL_RECURSE)
  #endif
  				 rexecutor_many(m, in, out,
  						p->nodeu.hc2hc.recurse,
  						istride * r, ostride,
  						r, istride, m * ostride,
  						FFTW_NORMAL_RECURSE);
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    else
  				 rexecutor_many_vector(m, in, out,
  						p->nodeu.hc2hc.recurse,
  						istride * r, ostride,
  						r, istride, m * ostride);
  #endif
  
  			    W = p->nodeu.hc2hc.tw->twarray;
  			    codelet = p->nodeu.hc2hc.codelet;
  			    HACK_ALIGN_STACK_EVEN;
  			    codelet(out, W, m * ostride, m, ostride);
  			    break;
  		       case FFTW_COMPLEX_TO_REAL:
  			    W = p->nodeu.hc2hc.tw->twarray;
  			    codelet = p->nodeu.hc2hc.codelet;
  			    HACK_ALIGN_STACK_EVEN;
  			    codelet(in, W, m * istride, m, istride);
  
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    if (recurse_kind == FFTW_NORMAL_RECURSE)
  #endif
  				 rexecutor_many(m, in, out,
  						p->nodeu.hc2hc.recurse,
  						istride, ostride * r,
  						r, m * istride, ostride,
  						FFTW_NORMAL_RECURSE);
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    else
  				 rexecutor_many_vector(m, in, out,
  						p->nodeu.hc2hc.recurse,
  						istride, ostride * r,
  						r, m * istride, ostride);
  #endif
  			    break;
  		       default:
  			    goto bug;
  		   }
  
  		   break;
  	      }
  
  	 case FFTW_RGENERIC:
  	      {
  		   int r = p->nodeu.rgeneric.size;
  		   int m = n / r;
  		   fftw_rgeneric_codelet *codelet = p->nodeu.rgeneric.codelet;
  		   fftw_complex *W = p->nodeu.rgeneric.tw->twarray;
  
  		   switch (p->nodeu.rgeneric.dir) {
  		       case FFTW_REAL_TO_COMPLEX:
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    if (recurse_kind == FFTW_NORMAL_RECURSE)
  #endif
  				 rexecutor_many(m, in, out,
  						p->nodeu.rgeneric.recurse,
  						istride * r, ostride,
  						r, istride, m * ostride,
  						FFTW_NORMAL_RECURSE);
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    else
  				 rexecutor_many_vector(m, in, out,
  						p->nodeu.rgeneric.recurse,
  						istride * r, ostride,
  						r, istride, m * ostride);
  #endif
  
  			    codelet(out, W, m, r, n, ostride);
  			    break;
  		       case FFTW_COMPLEX_TO_REAL:
  			    codelet(in, W, m, r, n, istride);
  
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    if (recurse_kind == FFTW_NORMAL_RECURSE)
  #endif
  				 rexecutor_many(m, in, out,
  						p->nodeu.rgeneric.recurse,
  						istride, ostride * r,
  						r, m * istride, ostride,
  						FFTW_NORMAL_RECURSE);
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
  			    else
  				 rexecutor_many_vector(m, in, out,
  						p->nodeu.rgeneric.recurse,
  						istride, ostride * r,
  						r, m * istride, ostride);
  #endif
  			    break;
  		       default:
  			    goto bug;
  		   }
  
  		   break;
  	      }
  
  	 default:
  	    bug:
  	      fftw_die("BUG in rexecutor: invalid plan\n");
  	      break;
       }
  }
  
  static void rexecutor_simple_inplace(int n, fftw_real *in,
  				     fftw_real *out,
  				     fftw_plan_node *p,
  				     int istride,
  				     fftw_recurse_kind recurse_kind)
  {
       switch (p->type) {
  	 case FFTW_REAL2HC:
  	      HACK_ALIGN_STACK_ODD;
  	      (p->nodeu.real2hc.codelet) (in, in, in + n * istride,
  					  istride, istride, -istride);
  	      break;
  
  	 case FFTW_HC2REAL:
  	      HACK_ALIGN_STACK_ODD;
  	      (p->nodeu.hc2real.codelet) (in, in + n * istride, in,
  					  istride, -istride, istride);
  	      break;
  
  	 default:
  	      {
  		   fftw_real *tmp;
  
  		   if (out)
  			tmp = out;
  		   else
  			tmp = (fftw_real *) fftw_malloc(n * sizeof(fftw_real));
  
  		   rfftw_executor_simple(n, in, tmp, p, istride, 1, 
  					 recurse_kind);
  		   rfftw_strided_copy(n, tmp, istride, in);
  
  		   if (!out)
  			fftw_free(tmp);
  	      }
       }
  }
  
  static void rexecutor_many_inplace(int n, fftw_real *in,
  				   fftw_real *out,
  				   fftw_plan_node *p,
  				   int istride,
  				   int howmany, int idist,
  				   fftw_recurse_kind recurse_kind)
  {
       switch (p->type) {
  	 case FFTW_REAL2HC:
  	      {
  		   fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;
  		   int s;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, in + s * idist,
  				in + n * istride + s * idist,
  				istride, istride, -istride);
  
  		   break;
  	      }
  
  	 case FFTW_HC2REAL:
  	      {
  		   fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;
  		   int s;
  
  		   HACK_ALIGN_STACK_ODD;
  		   for (s = 0; s < howmany; ++s)
  			codelet(in + s * idist, in + n * istride + s * idist,
  				in + s * idist,
  				istride, -istride, istride);
  
  		   break;
  	      }
  
  	 default:
  	      {
  		   int s;
  		   fftw_real *tmp;
  		   if (out)
  			tmp = out;
  		   else
  			tmp = (fftw_real *) fftw_malloc(n * sizeof(fftw_real));
  
  		   for (s = 0; s < howmany; ++s) {
  			rfftw_executor_simple(n,
  					      in + s * idist,
  					      tmp,
  					      p, istride, 1, recurse_kind);
  			rfftw_strided_copy(n, tmp, istride, in + s * idist);
  		   }
  
  		   if (!out)
  			fftw_free(tmp);
  	      }
       }
  }
  
  /* user interface */
  void rfftw(fftw_plan plan, int howmany, fftw_real *in, int istride,
  	   int idist, fftw_real *out, int ostride, int odist)
  {
       int n = plan->n;
  
       if (plan->flags & FFTW_IN_PLACE) {
  	  if (howmany == 1) {
  	       rexecutor_simple_inplace(n, in, out, plan->root, istride,
  					plan->recurse_kind);
  	  } else {
  	       rexecutor_many_inplace(n, in, out, plan->root, istride, howmany,
  				      idist, plan->recurse_kind);
  	  }
       } else {
  	  if (howmany == 1) {
  	       rfftw_executor_simple(n, in, out, plan->root, istride, ostride,
  				     plan->recurse_kind);
  	  } else {
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
                 int vector_size = plan->vector_size;
                 if (vector_size <= 1)
  #endif
  		    rexecutor_many(n, in, out, plan->root, istride, ostride,
  				   howmany, idist, odist,
  				   plan->recurse_kind);
  #ifdef FFTW_ENABLE_VECTOR_RECURSE
                 else {
                      int s;
                      int num_vects = howmany / vector_size;
                      fftw_plan_node *root = plan->root;
  
                      for (s = 0; s < num_vects; ++s)
                           rexecutor_many_vector(n,
  					       in + s * (vector_size * idist),
  					       out + s * (vector_size * odist),
  					       root,
  					       istride, ostride,
  					       vector_size, idist, odist);
  
                      s = howmany % vector_size;
                      if (s > 0)
                           rexecutor_many(n,
  					in + num_vects * (vector_size*idist),
  					out + num_vects * (vector_size*odist),
  					root,
  					istride, ostride,
  					s, idist, odist,
  					FFTW_NORMAL_RECURSE);
                 }
  #endif
  	  }
       }
  }
  
  void rfftw_one(fftw_plan plan, fftw_real *in, fftw_real *out)
  {
       int n = plan->n;
  
       if (plan->flags & FFTW_IN_PLACE)
  	  rexecutor_simple_inplace(n, in, out, plan->root, 1,
  				   plan->recurse_kind);
       else
  	  rfftw_executor_simple(n, in, out, plan->root, 1, 1,
  				plan->recurse_kind);
  }
  